Quantification of wine fault markers and their relation with risk factors

Abstract

While there have been numerous studies on individual wine faults and their risk factors little is known about their incidence and overall relationship to risk factors when purchased. To assess this relationship 100 wines produced in Missouri were randomly selected from the approximately 2500 available for sale in 2015- 2016. The wines collected went under a battery of tests for selected wine faults, flaws and known risk factors for problem development. The physical assessments included in this study where visual faults such as haze, sediment, excess turbidity and fill height from top of the bottle. Volatile compounds related to Brettanomyces sp. infection and cork taint were quantified as well as the undesirable aromas compounds H2S and 1-octen-3-ol, and acetic acid. Additional risk factors for fault development such as low free SO[subscript 2], high pH (above pH 3.7) and residual sugar were also assessed. Tested risk factors have varied greatly with wines having a pH value from 2.97-4.11, and free and total SO[subscript 2] varying from 0-118 mg/L and 3.6-324.4 mg/L respectively. While none of the wines exceeded current US legal limits for SO[subscript 2], 6% ([plus or minus]15%, for all MO wines at 95% CI) exceeded EU limits for total SO[subscript 2]. Conversely, 84% of the wines did not meet the free SO[subscript 2] requirement of 0.8 ppm based upon pH. At a fault recognition >|10|[micro]g/L for H[subscript 2]S 23% of the wines exceeded acceptable levels being considered faulted with no significant differences between categorical variables (e.g. red or white wine, closure type, fill volume etc.). This study is only one small sub-set of one region; to best understand how this data fits in with the wine industry as a whole, additional surveys are warranted. However, there is no reason to believe that this region is any different than would be found elsewhere.